Cutting assembly for removing a windshield and method relating to same

ABSTRACT

The cutting assembly functions to sever the urethane bed bonding a windshield to a vehicle. The assembly comprises a reciprocating air gun connected with a cutting blade by a shaft. The blade has a straight front cutting edge about 4 inches in width. The blade is reciprocated in and out of the bed to sever it.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of prior pending U.S. patentapplication Ser. No. 09/633,074 filed Aug. 4, 2000, which is acontinuation of U.S. patent application Ser. No. 08/781,954 filed Dec.2, 1996. The entire disclosures of the prior applications areincorporated herein it their entireties.

FIELD OF THE INVENTION

This invention relates to an assembly and method for separating a glasswindshield from a vehicle urethane bed by severing the bed along itslength.

BACKGROUND OF THE INVENTION

In the process of securing a glass windshield to a new car or truck, themanufacturer first extrudes a bead or “bed” of urethane onto the “pinchweld” extending around the perimeter of the window opening. The urethanebed bonds to the pinch weld surface. The glass windshield then is seatedon the bed and bonds to it, forming a liquid-tight seal.

The urethane bed is hard and tough and not easily penetrated. Itcommonly has a thickness of about {fraction (1/4)} inch and width ofabout ⅓-{fraction (3/4)} inches, widening to about 3½-4″ at the corners.

If the windshield is to be replaced, an installer severs the bed alongits length, just beneath the inside surface of the glass, leaving thebase portion of the bed in place. He then primes the cut surface of thebed, deposits a new bead of urethane on the primed surface and seats thereplacement windshield onto the fresh bead to bond it in place.

Up to about the end of the 1980's installers used a manually operatedknife to sever the urethane bed. The knife was generally L-shaped,having a narrow sharpened blade and a shank or handle equipped with handgrips. The installer would first work the point of the blade inwardly topenetrate the bed and would then reciprocate the blade with short in andout strokes while pulling the blade sideways to saw through the urethanebed along its length.

Commencing about 1990, two types of powered tools were introducedcommercially, to replace the manually operated tools. These poweredtools mimicked the manually operated knife in several structural andoperational respects.

The first type of tool involved an L-shaped blade and shank powered byan electric motor. The blade was oscillated from side to side. The bladewas pointed at its end and narrow (about {fraction (1/2)} inch wide), tofacilitate initial manual penetration. The side edge of the blade wassharpened, so that a lateral cutting action was produced.

The second type of tool involved reciprocating a blade which wouldextend in and out of a sleeve. The blade was actuated by an electricmotor. Again, the blade was pointed and narrow (about {fraction (1/2)}inch width), to facilitate initial penetration. The “throw” or distanceadvanced by the blade was short, about {fraction (1/2)} inch.

In use, these tools were characterized by several problems. Moreparticularly:

-   -   Cutting with them was slow. The depth and width of the cut were        small, requiring a great many cuts to complete the job.        Typically it would take about 15-20 minutes to cut the        windshield free;    -   Using the prior art assemblies was laborious. The installer        would have to apply a sideways pull to these tools, particularly        when cutting along the horizontal legs of the bed;    -   It was common to crack the glass when first penetrating the bed.        This could leave broken glass on the dash and elsewhere, which        was undesirable;    -   The cuts made by the tools were shallow. One could only cut into        the bed with these tools about {fraction (1/2)} inch at a time.        This meant that at the corners, where the bed width was        greatest, it would take prolonged cutting to complete severing        the bed. In practice, the installer would revert to using a hand        knife at the corners or would break off the glass at the corners        and have to later complete the cut by hand of the corner        urethane with its embedded glass. In the course of hand cutting        the corners, the installer would commonly press hard with his        head against the windshield to assist his cutting—this was known        to lead to neck injuries;    -   The cut surface produced by the blades of these powered tools        was irregular (jagged and undulating). This was undesirable as        the newly extruded bead would in part reproduce this underlying        irregularity and the new windshield would then not seat flush        against the bed surface. This could lead to a poor seal and        subsequent leaking;    -   The electric motor-driven tools of the prior art were generally        bulky and difficult to work with in confined space, such as the        apex between the vehicle dashboard and the inside surface of the        windshield;    -   The prior art blades were fragile and expensive—breakage was a        problem; and    -   It was necessary to use soapy water as a coolant and lubricant        for the narrow, rapidly moving blades. After the cut was        complete, the cut surface needed to be carefully washed to        remove soap, as it was detrimental to getting a good bond when        new urethane was laid on.

SUMMARY OF THE INVENTION

The preferred form of the invention involves combining the followingfeatures:

-   -   using a reciprocating air gun which delivers a high impact blow        with a stroke length of about {fraction (1/2)} inch;    -   matching the air gun with a wide, flat blade having a        transverse, straight front cutting edge which is at least 2        inches wide and preferably is about 4 inches wide. The blade        should be stiff but have sufficient lateral flexibility so as to        conform to the curvature of the windshield when manually pressed        thereagainst—preferably the blade can be about 4 inches in        length and formed of about 0.05 inch thick stainless steel;    -   the blade should also narrow from its front cutting edge to its        rear connection end. This allows the blade to be twisted by the        user as it is being worked around a corner;    -   connecting the blade with the gun with a slender, elongate,        substantially rigid shaft which will transmit the impact yet can        extend into the narrow apex space between the dashboard and the        windshield while spacing the gun well away from this confined        area;    -   the blade and shaft being substantially coplanar so there are no        significant protrusions at the connection point between blade        and shaft.

It has been found that this combination provides a cutting assemblyhaving the following attributes:

-   -   The air gun is capable of driving the wide blade into the tough        urethane bed to make a clean incision without damage to the bed;    -   The cutting stroke and blade are sufficiently long to enable the        blade to cut through even the wide corners of the bed—this can        typically be accomplished in 4 or 5 strokes;    -   No side pull is required—the blade cuts with an in and out        stroke. The installer need only support and guide the device and        does not need to press with his head against the inner surface        of the windshield;    -   Narrowing the blade from front to back enables the user to twist        it somewhat to facilitate cutting at the corners and minimizes        having protruding structure at the connecting point of blade and        shaft, which could cause damage to the dashboard or windshield;    -   Surprisingly, the cut surface of the bed is found to be smooth        and free of irregularities;    -   Blade breakage is reduced; and

The removal of a windshield is accomplished in about 3 minutes ascompared to the 15-20 minutes required for the prior art assemblies.

In one broad aspect, the invention involves a windshield removalassembly for cutting a urethane bed securing a glass windshield having acurved surface to a vehicle at an edge of a windshield opening formed bythe vehicle, there being a narrowing apex space between the windshieldand a vehicle part forming the opening, comprising: a reciprocating airgun; a rigid, elongated shaft having inner and outer ends and beingconnected at its inner end with the gun for reciprocation thereby; and aflat thin steel blade of substantially constant thickness, said bladehaving front and rear ends, the blade rear end being connected to theshaft's outer end, the blade being substantially coplanar with theshaft, the blade having a substantially straight front edge which isbeveled on one side only to provide a non-sharpened top edge and asharpened bottom cutting edge, the blade narrowing from its front end toits rear end to about the width of the shaft, the blade beingsufficiently rigid to cut the urethane bed when reciprocated by the airgun but having sufficient lateral flexibility to conform to the curvedsurface of the windshield when pressed there against; the shaft beingoperative to space the blade from the gun sufficiently to allow theassembly to be used within the confines of the apex space; the air gunbeing operative to reciprocate the shaft and blade with sufficient forceto advance the blade through the urethane bed; the blade beingconfigured so that the non-sharpened top edge of the blade can bepressed against the glass of the windshield while the sharpened bottomcutting edge penetrates the urethane bed.

In another broad aspect, the invention involves a method for separatinga glass windshield from a vehicle urethane bed, comprising: providing areciprocating air gun having a cutting tool mounted thereto forreciprocation thereby, said cutting tool comprising a shaft connected atone end with the gun and at the other end with a flat blade having afront cutting edge of at least 2 inches width; reciprocating the bladelongitudinally, into and out of the bed, and severing the bed across itswidth; and progressively moving the blade along the length of the bed tosever it completely and leave a smooth cut surface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view showing the cutting assembly;

FIG. 2 is a top plan elevation of a portion of the assembly of FIG. 1;

FIG. 3 is a side elevation, partly in section, showing a portion of theassembly of FIG. 1; and

FIG. 4 is a schematic side view showing the cutting assembly in use.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The cutting assembly 1 comprises a reciprocating air gun 2 and a cuttingtool comprised of a shaft 3 and blade 4.

The air gun 2 is commercially available. An Ingersoll Rand Pneumaticmodel #117 or a Chicago Pneumatic model # CP715 gun is suitable. Theseguns can deliver high impact strokes to advance the blade 4 through theurethane bed 24. The shaft 3 is a {fraction (3/4)} inch diameter steelrod having an inner end 5 conventionally shaped to connect with the airgun 2. At its outer end 6, a slot 7 extends inwardly to receive theshank 8 of the blade 4. The upper surface of the rod end 6 forms arecess 9. The rod end 6 further forms bolt holes 10 extendingtransversely therethrough. Nuts 11 and bolts 12 are received in therecess 9 and holes 10 to secure the blade shank 8 to the rod end 6.

The blade 4 is substantially bell-shaped, is formed of stainless steel,has a width at the front edge 20 of about 4 inches, a length of 6 inchesand a thickness of 0.05 inches. While it is substantially rigid, it hassufficient lateral flexibility so that it will conform to the windshieldcurvature when pressed thereagainst. The blade 4 includes a 2 inch longshank 8 which is received in the rod slot 7. The blade 4 narrows fromfront to rear and its shank 8 has about the same width as the shaft 3,so that there are no significant lateral protuberances at the connectionpoint. More specifically, the front edge 20 is beveled on one side onlyto produce a top unsharpened edge which bears against the glass of thewindshield and a bottom sharpened cutting edge which penetrates theurethane bed 24 when the assembly is in use. The front edge 20 isstraight and sharpened.

When assembled and operated, the blade 4 reciprocates with a throw ortravel of about ½ inch. The blade is pressed against the inside surface22 of the glass windshield 23 and is driven into the urethane bed 24. Itsevers the bed just beneath the glass. The installer moves the assemblyalong the length of the bed by withdrawing the blade from the urethane,moving it to the next adjacent cut position and then again driving theblade in. The installer can also use water without lubricant as acooling agent while cutting the urethane bed.

1. A cutting tool for separating a glass windshield from a vehicle urethane bed, the cutting tool to be used with a reciprocating device, the cutting tool comprising: a shaft having inner and outer ends and being connected at its inner end with the reciprocating device for reciprocation thereby, wherein the shaft is rigid and elongated; a blade wherein the blade is flat and thin and has a substantially constant thickness, said blade having front and rear ends, the blade rear end being connected to the shaft's outer end, the blade being substantially coplanar with the shaft, the blade having a substantially straight front edge which is beveled on one side only to provide a non-sharpened top edge and a sharpened bottom cutting edge, the blade narrowing from its front end to its rear end to about the width of the shaft wherein said front end is wider than the width of the shaft, the blade being sufficiently rigid to cut the urethane bed when reciprocated by the reciprocating device, but having sufficient lateral flexibility to conform to a curved surface of the windshield when pressed thereagainst, the blade being configured so that the non-sharpened top edge of the blade can be pressed against the glass of the windshield while the sharpened bottom cutting edge penetrates the urethane bed; wherein the blade can be driven through the urethane bed by triggering the reciprocating device to reciprocate the blade longitudinally into and out of the urethane bed.
 2. The cutting tool as claimed in claim 1, wherein the cutting edge comprises a width of about 4 inches.
 3. The cutting tool as claimed in claim 1, wherein the shaft has a length operative to space the blade from the reciprocating device to allow the cutting tool be used within the confines of a narrowing apex space between the windshield and the vehicle.
 4. The cutting tool as claimed in claim 1, wherein the outer end of the shaft further comprises: a slot for receiving a shank of the blade; a recess on a first side of the shaft; and a plurality of bolt holes passing transversely from a second side of the shaft to the first side of the shaft and intersecting the slot and the recess, the bolt holes having a countersunk portion on the second side of the shaft.
 5. The cutting tool as claimed in claim 4, wherein the bolt holes are aligned along a longitudinal axis of the shaft.
 6. The cutting tool as claimed in claim 4, further comprising a plurality of bolts and a plurality of corresponding nuts, said plurality of bolts having head portions that are sized to be received within the countersunk portion of the bolt holes in the second side of the shaft, wherein the bolt holes and the recess allow for insertion of the bolts in the bolt holes to secure the blade within the slot of the shaft, the nuts positioned within the recess in the shank, whereby the countersunk portion of the bolt holes and recess prevent the head portions of the bolts and the nuts from extending beyond a circumference of the shaft, and thereby further prevent the bolt head and the nuts from scratching a dash or an interior portion of the vehicle.
 7. A cutting tool, to be used with a reciprocating air gun, for separating a glass windshield from a vehicle urethane bed, comprising: a shaft having inner and outer ends, said shaft being connectable at its inner end to the air gun for reciprocation thereby; and a flat blade mountable to the outer end of the shaft, said blade having a sharp transverse front cutting edge having a width of at least about 2 inches and sufficient lateral flexibility to substantially conform with the curvature of the windshield when pressed thereagainst in use.
 8. The tool as set forth in claim 7, wherein the blade cutting edge is straight when not in use and has a width of about 4 inches.
 9. The tool as set forth in claim 7, wherein the blade has a length of about 4 inches.
 10. The tool as set forth in claim 7, wherein the transverse front cutting edge is substantially straight and beveled on one side only to provide a non-sharpened top edge and a sharpened bottom cutting edge, the blade narrowing from its front end to its rear end to about the width of the shaft wherein said front end is wider than the width of the shaft.
 11. The tool as set forth in claim 10, wherein the blade is configured so that the non-sharpened top edge of the blade can be pressed against the glass windshield while the sharpened bottom cutting edge penetrates the urethane bed.
 12. A windshield removal assembly for cutting a urethane bed securing a glass windshield having a curved surface to a vehicle at an edge of a windshield opening formed by the vehicle, there being a narrowing apex space between the windshield and a vehicle part forming the opening, comprising: a reciprocating air gun; a rigid, elongated shaft having inner and outer ends and being connected at its inner end with the gun for reciprocation thereby; and a flat thin steel blade of substantially constant thickness, said blade having front and rear ends, the blade rear end being connected to the shaft's outer end, the blade being substantially coplanar with the shaft, the blade having a substantially straight front edge which is beveled on one side only to provide a non-sharpened top edge and a sharpened bottom cutting edge, the blade narrowing from its front end to its rear end to about the width of the shaft, the blade being sufficiently rigid to cut the urethane bed when reciprocated by the air gun but having sufficient lateral flexibility to conform to the curved surface of the windshield when pressed there against; the shaft being operative to space the blade from the gun sufficiently to allow the assembly to be used within the confines of the apex space; the air gun being operative to reciprocate the shaft and blade with sufficient force to advance the blade through the urethane bed; the blade being configured so that the non-sharpened top edge of the blade can be pressed against the glass of the windshield while the sharpened bottom cutting edge penetrates the urethane bed.
 13. The windshield removal assembly as set forth in claim 12, wherein the blade has a thickness of about 0.05 inches and a length of about 6 inches, and the blade front cutting edge has a width of about 4 inches.
 14. The windshield removal assembly as set forth in claim 12, wherein the air gun has a stroke length of about 0.5 inches.
 15. The windshield removal assembly as set forth in claim 12, wherein the outer end of the shaft further comprises: a slot for receiving a shank of the blade; a recess on a first side of the shaft; and a plurality of bolt holes passing transversely from a second side of the shaft to the first side of the shaft and intersecting the slot and the recess, the bolt holes having a countersunk portion on the second side of the shaft. 